The present invention relates generally to liquid dispensers, and particularly to a dosing pump for a viscous liquid dispenser.
Viscous liquid dispensers are well known in the art for dispensing any manner of viscous liquid, for example lotions, soap, and the like. The conventional dispensers utilize a wide variety of pumping mechanisms which allow a user to depress or manipulate a pump actuator in order to dispense liquid from the dispenser. Exemplary devices are shown, for example, in U.S. Pat. Nos. 5,810,203; 5,379,919; 5,184,760; and 4,174,056.
Conventional dispensers and pump mechanisms are configured generally for vertical mode operation. In other words, the dispenser stands generally upright with the pumping device configured at the top of the unit. These pump devices are generally vented around the stem of the pump and should a user attempt to use the dispenser in a horizontal mode, the dispenser will, in all likelihood, leak around the pump stem.
An additional problem noted with conventional pumps, particularly lotion or soap dispenser pumps, is that there is a tendency for leakage of residual liquid left in the pump head. Certain types of combination pumps, such as peristaltic pumps common to liquid skin care product dispensers, incorporate a spring and ball check valve system in the discharge area to prevent leaking. However, this type of check valve system is relatively expensive and complicated, and the components may be subject to corrosion and/or sticking when used with certain chemical compositions.
Diaphragm type valves are used in certain applications, for example squeeze actuated bottles of hand lotion, in which the bottle is squeezed by a user to provide the liquid pressure required to open the diaphragm valve. However, with these configurations, there is no discreet control over the amount of liquid dispensed.
Thus, there is a need in the art for a dosing pump that can dispense a metered amount of viscous liquid in a horizontal as well as a vertical mode while preventing leakage from around the pump mechanism without complicated check valve devices.
Objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
The present invention provides a unique dosing pump that is particularly well suited for viscous liquid dispensers, for example, soap dispensers, lotion dispensers, and the like. The pump may be oriented in a generally horizontal configuration and thus allows greater flexibility as to the design and configuration of a dispenser utilizing the pump.
The pump may be utilized with any manner or shape of dispenser. The dispenser will generally comprise a housing member or members that define a liquid reservoir. The pump includes a pump chamber that is in communication with the liquid reservoir. In one embodiment, the pump chamber may be defined internally of the dispenser housing. For example, the pump chamber may comprise an integrally molded component of the housing. In an alternative embodiment, the pump chamber may be configured on the outside of the reservoir or housing with a channel or passage defining a liquid communication path between the reservoir and the pump chamber. It should be appreciated that any number of configurations may be utilized to define a pump chamber that is in fluid communication with a liquid reservoir.
The pump chamber has a volume that generally defines the metered dose of liquid to be dispensed. A dispensing orifice is defined in the pump chamber. The orifice may be defined in any wall member of the chamber, or in one particular embodiment according to the invention, the orifice may be defined through a pump cylinder.
A pump mechanism is configured with the pump chamber to pressurize liquid within the pump chamber upon actuation of the pump mechanism. The pump mechanism may be any member or configuration of components that pressurizes the liquid contained within the chamber in order to expel or dispense the liquid through the dispensing orifice. In one particular embodiment according to the invention, the pump mechanism includes a pump cylinder that is slidably disposed and retained in the pump chamber. The pump cylinder is moveable from a rest position to a pressurizing position and may be biased to the rest position. An actuator is configured with the pump cylinder and provides a device for an operator to move the pump cylinder to its pressurizing position in order to dispense liquid out the dispensing orifice. The pump mechanism may comprise a shaft and piston type of arrangement wherein the piston is sealed against the chamber walls. Upon movement of the shaft and piston within the pump chamber, any liquid contained within the chamber is pressurized and ultimately dispensed out the dispensing orifice defined in the chamber. The pump mechanism may be a relatively simple diaphragm that pressurizes the pump chamber upon being compressed.
In one embodiment of the invention, the dispensing orifice is defined as a longitudinal channel within a pump cylinder that is slidable within the pump chamber. The channel terminates at a dispensing orifice defined in a delivery end of the cylinder. The pump cylinder may be biased by a spring member towards its rest position. The spring member may be operably configured within the pump chamber or outside of the pump chamber. Any type of resilient member may be utilized to bias the pump cylinder.
The invention is not limited to any particular type of device for actuating the pump. In one particular embodiment, the actuator may comprise a panel member that is pivotally mounted to the dispenser housing. The panel member rests against a front end of a pump cylinder or shaft and thus moves the pump cylinder or shaft upon an operator depressing the panel member. In an alternate embodiment, the actuator may comprise a panel member plate, button or the like attached directly to the front end of the pump cylinder or shaft. The actuator may be configured in any shape to contribute to the aesthetically pleasing look of the dispenser.
A check valve mechanism is operably disposed in the opening between the pump chamber and the liquid reservoir. Upon actuation of the pump, the check valve mechanism moves to seal the pump chamber so that the liquid within the chamber is pressurized. Upon release of the pump actuator, the check valve mechanism moves to unseal the pump chamber so that a metered amount of viscous liquid is able to flow automatically from the reservoir into the pump chamber for dispensing upon the next subsequent actuation of the pump. The check valve mechanism may take on a number of configurations. For example, the check valve mechanism may comprise a ball seated within a recess that defines the opening between the pump chamber and the reservoir. The recess may include a tapered sealing surface against which the ball seals upon actuation of the pump, and a lower recess portion into which the ball falls by gravity upon release of the pump.
In an alternate embodiment, the check valve mechanism may comprise a resilient flap member that is disposed across the opening between the pump chamber and the reservoir. Upon pressurization of the pump chamber, the flap member seals the opening to the reservoir. Upon release of the pump, the flap member hangs freely. The static head pressure of the liquid within the reservoir will move the flap member away from the opening and cause the liquid to refill the pump chamber.
In still another embodiment of the check valve mechanism, a conical plug member takes the place of the ball. The plug member is moveable into and out of engagement with a tapered sealing surface defining the opening in the back of the pump chamber. The plug member may have the general shape of the recess defining the tapered sealing surface, and thus is capable of floating freely within the recess. In an alternate embodiment, the plug member may be guided by a spring loaded rod that is operably connected with the pump piston. The rod may move longitudinally within a recess or channel defined through the piston as the piston and shaft are moved within the pump chamber.
In still another embodiment, the check valve mechanism may comprise an elongated shuttle type valve that is slidable within the opening between the pump chamber and reservoir. The shuttle valve includes a sealing member that seals the opening upon actuation of the pump device. Upon release of the pump, the shuttle valve unseals, and liquid is free to flow past the shuttle valve and into the pump chamber.
The pump according to the invention also includes a restriction device disposed operably across the dispensing orifice. The restriction device is a generally resilient member that opens or moves upon sufficient liquid pressure build up within the pump chamber. Upon release of the pump mechanism, the restriction device serves two purposes. As the pump mechanism, for example the piston and shaft configuration, cylinder, or diaphragm configuration, moves back to its rest position, the restriction device defines a vent path for venting the pump chamber. As the vacuum within the chamber increases upon release of the pump mechanism, the resilient member is drawn towards the pump chamber and thus opens to define a vent path into the chamber. Once the pump mechanism has reached its rest position, the restriction device closes to completely seal the dispensing orifice, and thus, prevents leakage or drippage from the orifice. With the restriction device disposed within the dispensing orifice, it is not necessary to separately vent the pump chamber around the pump shaft or cylinder or to separately vent the dispenser reservoir.
The invention will be described in greater detail below through embodiments illustrated in the figures.